It’s official, Schema.org has launched its schema markup validator tool at validator.schema.org. The markup validator helps you validate your structured data on your site that is used for general purposes, outside of the Google rich results.
Reviews stars markup allows you to add an overall rating to your SERPs. By adding specific structured data to your page you can enable it to show a star rating below the meta description. This is a great way catch the eye of potential customers..
What is an entity? An entity is a thing or a concept that is singular, that is unique, that is well-defined and that is distinguishable. Today's internet is truly a semantic web of linked data. It also allows people to search for information.